Fixes issue with Table not scrolling completely to the end #12651

Made the Table notice if the user is trying to scroll to an item on the
last "page" and in those cases actually scroll to that item, not just to
the page's first item as it did before.

Change-Id: I47df33c75aa9b7e4f9a5f4bd5daeb301028517e8

1 files changed, 28 insertions, 4 deletions

diff --git a/server/src/com/vaadin/ui/Table.java b/server/src/com/vaadin/ui/Table.java
index bd2b7828de..32ed738697 100644
--- a/server/src/com/vaadin/ui/Table.java
+++ b/server/src/com/vaadin/ui/Table.java
@@ -427,6 +427,12 @@ public class Table extends AbstractSelect implements Action.Container,
     private int currentPageFirstItemIndex = 0;
 
     /**
+     * Index of the "first" item on the last page if a user has used
+     * setCurrentPageFirstItemIndex to scroll down. -1 if not set.
+     */
+    private int currentPageFirstItemIndexOnLastPage = -1;
+
+    /**
      * Holds value of property selectable.
      */
     private boolean selectable = false;
@@ -1477,12 +1483,14 @@ public class Table extends AbstractSelect implements Action.Container,
         }
 
         /*
-         * FIXME #7607 Take somehow into account the case where we want to
-         * scroll to the bottom so that the last row is completely visible even
-         * if (table height) / (row height) is not an integer. Reverted the
-         * original fix because of #8662 regression.
+         * If the new index is on the last page we set the index to be the first
+         * item on that last page and make a note of the real index for the
+         * client side to be able to move the scroll position to the correct
+         * position.
          */
+        int indexOnLastPage = -1;
         if (newIndex > maxIndex) {
+            indexOnLastPage = newIndex;
             newIndex = maxIndex;
         }
 
@@ -1494,6 +1502,20 @@ public class Table extends AbstractSelect implements Action.Container,
                 currentPageFirstItemId = null;
             }
             currentPageFirstItemIndex = newIndex;
+
+            if (needsPageBufferReset) {
+                /*
+                 * The flag currentPageFirstItemIndexOnLastPage denotes a user
+                 * set scrolling position on the last page via
+                 * setCurrentPageFirstItemIndex() and shouldn't be changed by
+                 * the table component internally changing the firstvisible item
+                 * on lazy row fetching. Doing so would make the scrolling
+                 * position not be updated correctly when the lazy rows are
+                 * finally rendered.
+                 */
+                currentPageFirstItemIndexOnLastPage = indexOnLastPage;
+            }
+
         } else {
 
             // For containers not supporting indexes, we must iterate the
@@ -3447,6 +3469,8 @@ public class Table extends AbstractSelect implements Action.Container,
         if (getCurrentPageFirstItemIndex() != 0 || getPageLength() > 0) {
             target.addVariable(this, "firstvisible",
                     getCurrentPageFirstItemIndex());
+            target.addVariable(this, "firstvisibleonlastpage",
+                    currentPageFirstItemIndexOnLastPage);
         }
     }